Nonaqueous electrolyte battery and production method therefor

ABSTRACT

Disclosed is a non-aqueous electrolyte battery comprising: a flat outer jacket comprising a metal sheet and having two primary flat portions facing each other; two active material layers of a first polarity respectively carried on inner surfaces of the flat portions; an electrode plate of a second polarity disposed in a position facing with each of the active material layers; and a separator layer interposed between each of the active material layers and the electrode plate of a second polarity, with the outer jacket serving as a current collector of the active material layers.

TECHNICAL FIELD

[0001] The present invention relates to a non-aqueous electrolytebattery and the method of producing the same.

BACKGROUND ART

[0002] Recently, an increasing number of electronic equipment such as AVequipment and personal computers are becoming cordless and portable.With this development, many non-aqueous electrolyte batteries with highenergy density containing a non-aqueous electrolyte, are being adopted.Of the non-aqueous electrolyte batteries, lithium secondary batteriesare the ones that are most widely used in practical applications.

[0003] For the negative electrode of the lithium secondary battery,negative electrode materials capable of absorbing and desorbing lithiumas well as having a low electric potential closer to that of lithium,such as graphite and amorphous carbon, are being employed. On the otherhand, for the positive electrode, for example, lithium-containingtransition metal compounds capable of absorbing and desorbing lithium aswell as having a high electric potential, such as LiCoO₂ and LiMn₂O₄,are being employed as the positive electrode material.

[0004] The electrode plate of the non-aqueous electrolyte battery isproduced, for example, in the following manner.

[0005] Firstly, a slurry-like electrode mixture which contains apositive electrode material or a negative electrode material, a binderand a dispersion medium, is prepared. The electrode mixture is appliedonto a current collector or a core material such as a metal sheet, metalmesh, metal lath sheet and punched metal, which is then rolled, driedand cut into a desired shape to give an electrode plate.

[0006] The non-aqueous electrolyte is prepared by dissolving a lithiumsalt such as LiPF₆ or LiBF₄ in a non-aqueous solvent. As the non-aqueoussolvent, for example, ethylene carbonate, dimethyl carbonate, ethylmethyl carbonate, propylene carbonate, diethyl carbonate and the likeare employed. These days, a mixed solvent of an open-chain compound anda cyclic compound is in great use.

[0007] A conventional non-aqueous electrolyte battery comprises, forexample, an electrode plate group, which is produced by spirally windinga positive electrode and a negative electrode with a separator disposedtherebetween, and a cylindrical-type or square-type container forhousing the electrode plate group together with a non-aqueouselectrolyte. The opening of the container is sealed by a sealing platewhich also serves as an external terminal. A battery having suchstructure is difficult to be designed thinner. However, with the recenttrend for more compact electronic equipment, there is a strong demandfor a small, light-weight battery with a sufficient energy density whichcan be accommodated in a limited space. Even batteries with a thicknessof less than several millimeters are demanded in many cases.

[0008] For this reason, polymer electrolytes are recently being appliedto batteries. As a polymer electrolyte, a gel electrolyte is employed,which comprises a liquid non-aqueous electrolyte and a polymer retainingthe same. The polymer electrolyte has both functions of transferringions and separating electrode plates. Thin polymer batteries with highenergy density have also been developed, which are fabricated bystacking a positive electrode and a negative electrode with a separatorlayer containing the polymer electrolyte disposed therebetween andcovering the whole by an outer jacket.

[0009] The separator layer containing the polymer electrolyte is formed,for example, by causing a microporous membrane or non-woven fabric eachcontaining a gel-forming agent to absorb a liquid non-aqueouselectrolyte and sandwiching it between electrode plates. As thegel-forming agent, a polymer capable of absorbing a liquid non-aqueouselectrolyte and forming a gel electrolyte, is employed.

[0010] A separator layer composed only of a polymer electrolyte can alsobe formed. Examples of the method of forming such separator include theone which involves mixing a gel-forming agent and a solvent to prepare apaste, stacking electrode plates with the paste interposed therebetweenand drying the whole, followed by causing the gel-forming agent toabsorb the liquid non-aqueous electrolyte. Additionally, another methodis known, which involves mixing a gel-forming agent and a liquidnon-aqueous electrolyte to prepare a paste and stacking electrode plateswith the paste interposed therebetween.

[0011] Japanese Unexamined Patent Publication No. 2000-67850 discloses atechnique of integrating electrode plates with a separator layercomprising a polymer electrolyte interposed therebetween.

[0012] In each of Japanese Unexamined Patent Publication Nos.2000-12084, 2000-156209 and 2000-223108, there is disclosed an electrodeplate group, formed by disposing a pair of electrode plates whichcomprises a pair of current collectors and an active material layerformed on one surface of each of the current collector so as to faceeach other with the active material layers disposed facing inwardly, andsandwiching an electrode plate of a different polarity by the pair ofthe electrode plates with a separator layer comprising a polymerelectrolyte interposed therebetween. There is also disclosed a batteryin which an electrode plate group is accommodated in an outer jacketmade of a laminate sheet comprising a resin layer and metal foil.

[0013] Japanese Unexamined Patent Publication No. Hei 11-265699discloses a battery in which an electrode plate group having a separatorlayer comprising a polymer electrolyte is accommodated in a bag-like,film-type outer jacket provided with a safety venting mechanism.

[0014] Japanese Examined Patent Publication No. Hei 9-506208 discloses abattery in which a flat, spirally wound electrode plate group having aseparator layer comprising a polymer electrolyte is accommodated in anenvelope-like outer jacket having an external terminal.

[0015] In each of the conventional thin batteries described above, theelectrode plate group is accommodated in an outer jacket which isseparately prepared. There is a limit on the simplification of the outerjacket structure, the reduction in thickness and improvement in energydensity of the battery, and the simplification of the batterymanufacturing process, as long as these are attempted based upon theidea of using a separately prepared outer jacket.

DISCLOSURE OF INVENTION

[0016] It is an object of the present invention to provide alight-weight, high-energy density, thin non-aqueous electrolyte batterywhich has a high flexibility in capacity design and a simplified outerjacket structure. In particular, it is an object of the presentinvention to provide a thin non-aqueous electrolyte battery having anovel structure in which the battery thickness and battery area havebeen reduced.

[0017] It is also an object of the present invention to provide anefficient method of producing a non-aqueous electrolyte battery, whichmethod allows a series of steps to be performed continuously without theneed to perform an outer-packing or sheathing step.

[0018] Namely, the present invention relates to a non-aqueouselectrolyte battery comprising:

[0019] an outer jacket comprising a metal sheet and having two primaryflat portions facing each other;

[0020] two active material layers of a first polarity respectivelycarried on inner surfaces of the flat portions;

[0021] an electrode plate of a second polarity disposed in a positionfacing with each of the active material layers; and

[0022] a separator layer interposed between each of the active materiallayers and the electrode plate of a second polarity,

[0023] the outer jacket serving as a current collector of the activematerial layers.

[0024] The present invention also relates to the non-aqueous electrolytebattery in a double-stacked form, comprising: an additional electrodeplate of a first polarity disposed adjacent to the electrode plate of asecond polarity with a separator layer interposed therebetween; and anadditional electrode plate of a second polarity disposed adjacent to theadditional electrode plate of a first polarity with a separator layerinterposed therebetween.

[0025] Further, the present invention relates to a non-aqueouselectrolyte battery comprising a lead electrically connected to theelectrode plate of a second polarity, one end of the lead protrudingoutside from the outer jacket, and the lead being insulated from theouter jacket with resin.

[0026] It is preferable that the lead is provided with an overcurrentbreaking device sealed with resin at a portion thereof sandwichedbetween the peripheral portions of the outer jacket.

[0027] It is preferable that at least one of the separator layer and theactive material layers contain a polymer electrolyte.

[0028] It is preferable that the polymer electrolyte is a gelelectrolyte comprising a liquid non-aqueous electrolyte and a polymerretaining the same.

[0029] Further, the present invention relates to a non-aqueouselectrolyte battery wherein the outer jacket comprises a pair of metalsheets having flat portions facing each other or a single metal sheetfolded so as to have two flat portions facing each other, and peripheralportions facing each other of the pair of metal sheets or peripheralportions facing each other of the single metal sheet are joined.

[0030] It is preferable that the peripheral portions facing each otherare joined by laser welding or ultrasonic welding.

[0031] It is preferable that the metal sheet has a thickness of 10 to100 μm.

[0032] The present invention also relates to a method of producing anon-aqueous electrolyte battery comprising the steps of:

[0033] (1a) forming an active material layer of a first polarity on aflat portion of one surface of a metal sheet except for a peripheralportion thereof, thereby producing an outer electrode plate;

[0034] (2a) producing an electrode plate of a second polarity;

[0035] (3a) preparing a pair of outer electrode plates, disposing one ofthe outer electrode plates and the other outer electrode plate so as toface each other, with the active material layers disposed facinginwardly, and sandwiching the electrode plate of a second polarity bythe pair of outer electrode plates facing each other, with a separatorlayer interposed therebetween; and

[0036] (4a) joining peripheral portions of the pair of outer electrodeplates facing each other.

[0037] Further, the present invention relates to the method of producinga non-aqueous electrolyte battery,

[0038] wherein, in the step (1a), a plurality of active material layersof a first polarity are intermittently formed on a flat portion of onesurface of a band-shaped metal sheet except for a peripheral portionthereof, thereby producing an outer electrode plate assembly comprisinga plurality of outer electrode plate units aligned in a row and,

[0039] in the step (3a), a pair of the outer electrode plate assembliesare prepared, each outer electrode plate unit of one of the outerelectrode plate assemblies and each outer electrode plate unit of theother outer electrode plate assembly are successively disposed so as toface each other, with the active material layers disposed facinginwardly, and the electrode plate of a second polarity is successivelysandwiched by a pair of outer electrode plate units facing each other,with a separator layer interposed therebetween.

[0040] In the step (3a), an additional electrode plate of a firstpolarity may be disposed adjacent to the electrode plate of a secondpolarity, with a separator layer interposed therebetween, and anadditional electrode plate of a second polarity may be disposed adjacentto the additional electrode plate of a first polarity, with a separatorlayer interposed therebetween.

[0041] In the step (3a), a paste comprising a starting material of theseparator layer may be applied on the active material layer of a firstpolarity or the electrode plate of a second polarity to form theseparator layer.

[0042] It is preferable that the starting material of the separatorlayer contains a gel-forming agent.

[0043] As the gel-forming agent, a polymer capable of absorbing a liquidnon-aqueous electrolyte and forming a gel electrolyte, is employed.

[0044] The present invention also relates to a method of producing anon-aqueous electrolyte battery comprising the steps of:

[0045] (1b) preparing a metal sheet provided with a crease line or animaginary crease line at which the sheet is to be folded so as to havetwo flat portions facing each other;

[0046] (2b) forming a pair of active material layers of a first polarityon the flat portions, symmetrical with respect to the crease line orimaginary crease line, of one surface of the metal sheet except forperipheral portions thereof, thereby producing outer electrode plate;

[0047] (3b) producing an electrode plate of a second polarity;

[0048] (4b) folding the outer electrode plate at the crease line orimaginary crease line to sandwich the electrode plate of a secondpolarity by the pair of active material layers with a separator layerinterposed therebetween; and

[0049] (5b) joining peripheral portions of the outer electrode platefacing each other.

[0050] Herein, the imaginary crease line refers to a line dividing themetal sheet into two sections, which line is assumed as a measure orstandard for folding the metal sheet so as to have two flat portionsfacing each other.

[0051] The present invention also relates to the method of producing anon-aqueous electrolyte battery,

[0052] wherein, in the step (1b), a band-shaped metal sheet is prepared,which is provided with a crease line or an imaginary crease lineparallel with a longitudinal direction,

[0053] in the step (2b), plural pairs of active material layers of afirst polarity are intermittently formed on flat portions, symmetricalto the crease line or imaginary crease line, of one surface of theband-shaped metal sheet except for peripheral portions thereof, therebyproducing an outer electrode plate assembly comprising a plurality ofouter electrode plate units aligned in a row and,

[0054] in the step (4b), the electrode plate of a second polarity issuccessively sandwiched by a pair of active material layers of eachouter electrode plate unit, with the separator layer interposedtherebetween.

[0055] In the step (4b), an additional electrode plate of a firstpolarity may be disposed adjacent to the electrode plate of a secondpolarity with a separator layer interposed therebetween, and anadditional electrode plate of a second polarity may be disposed adjacentto the additional electrode plate of a first polarity with a separatorlayer interposed therebetween.

[0056] In the step (4b), a paste comprising a starting material of theseparator layer may be applied on the active material layer of a firstpolarity or the electrode plate of a second polarity, thereby formingthe separator layer.

[0057] It is preferable that the starting material of the separatorlayer contains a gel-forming agent.

[0058] As the gel-forming agent, a polymer capable of absorbing a liquidnon-aqueous electrolyte and forming a gel electrolyte, is employed.

BRIEF DESCRIPTION OF DRAWINGS

[0059]FIG. 1 is a vertical sectional view of an example of a non-aqueouselectrolyte battery comprising one stack in accordance with the presentinvention.

[0060]FIG. 2 is an oblique view of an example of an outer electrodeplate comprising a metal sheet serving as a current collector and anactive material layer formed on one surface of the same.

[0061]FIG. 3 is an oblique view of an example of an outer electrodeplate with the region to be provided with an adhesive indicated bydashed lines.

[0062]FIG. 4 is a vertical sectional view of an example of an electrodeplate group comprising one stack.

[0063]FIG. 5 is a vertical sectional view showing a main part of anexample of a non-aqueous electrolyte battery comprising one stack inaccordance with the present invention, which is provided with a PTCdevice.

[0064]FIG. 6 is a sectional view of an example of outer electrode plateassembly, prior to cutting.

[0065]FIG. 7 is a sectional view of an example of an outer electrodeplate assembly having a separator layer, prior to cutting.

[0066]FIG. 8 is an oblique view showing an example of the internalstructure of an electrode plate group assembly, prior to cutting.

[0067]FIG. 9 is a vertical sectional view of an example of an electrodeplate group assembly, prior to cutting.

[0068]FIG. 10 is a vertical sectional view of an example of a batteryassembly, prior to cutting.

[0069]FIG. 11 is a vertical sectional view of an example of anotherelectrode plate group assembly prior to cutting.

[0070]FIG. 12 is a vertical sectional view of an example of anon-aqueous electrolyte battery comprising two stacks in accordance withthe present invention.

[0071]FIG. 13 is a vertical sectional view of an example of an electrodeplate group comprising two stacks.

[0072]FIG. 14 is a plane view of an example of a non-aqueous electrolytebattery in accordance with the present invention.

[0073]FIG. 15 is an example of a sectional view taken on line I-I inFIG. 14.

[0074]FIG. 16 is an example of a sectional view taken on line II-II inFIG. 14.

[0075]FIG. 17 is an example of a sectional view taken on line III-III inFIG. 14.

[0076]FIG. 18 is an oblique view of an uncompleted non-aqueouselectrolyte battery with an outer electrode plate thereof bent halfway.

[0077]FIG. 9 is a diagram showing the proceeding of a method ofproducing a non-aqueous electrolyte battery in accordance with thepresent invention, which employs an outer electrode plate assembly.

[0078]FIG. 20 is another example of a sectional view taken on line I-Iin FIG. 14.

[0079]FIG. 21 is another example of a sectional view taken on line II-IIin FIG. 14.

[0080]FIG. 22 is another example of a sectional view taken on lineIII-III in FIG. 14.

BEST MODE FOR CARRYING OUT THE INVENTION

[0081] Embodiment 1

[0082]FIG. 1 shows a vertical sectional view of a non-aqueouselectrolyte battery of Embodiment 1 in accordance with the presentinvention.

[0083] This battery comprises: an outer jacket comprising metal sheets102 and having two primary flat portions facing each other; two activematerial layers of a first polarity 103 respectively carried on innersurfaces of the flat portions; an electrode plate of a second polarity104 disposed in a position facing with each of the active materiallayers 103; and separator layers 107 each interposed between each of theactive material layers 103 and the electrode plate of a second polarity104, and the outer jacket also serves as the current collector of theactive material layers 103. The metal sheet 102 and the active materiallayers 103 respectively carried on the flat portions of the metal sheet,constitute an outer electrode plate 101.

[0084] The separator layer 107 contains a polymer electrolyte. It ispreferable that the active material layer 103 or an active materiallayer 106 of the electrode plate of a second polarity 104 contains apolymer electrolyte from the viewpoint of improving the charge/dischargecharacteristic of the battery. In order to provide a polymer electrolytein the active material layer, the polymer electrolyte is mixed with thestarting material of the active material layer to prepare an electrodemixture, and the electrode mixture is used to form an active materiallayer. Or alternatively, an active material layer containing agel-forming agent which comprises a cross-linking polymer is formed,and, after the cross-linking polymer is crosslinked, a liquidnon-aqueous electrolyte is absorbed in the active material layer.

[0085] A lead 109 is connected to the extension of a current collector105 which constitutes the electrode plate of a second polarity 104. Aninsulating resin 110 b is coated around the lead 109 at the portionsandwiched between the peripheral portions of the metal sheets 102.While the lead is not necessarily be provided to the outer electrodeplate 101, a lead 111 is welded so as to be sandwiched between theperipheral portions of the metal sheets 102, in FIG. 1.

[0086] A pair of the outer electrode plates 101 is joined at theperipheral portions facing each other of their respective metal sheets102. In this manner, since a pair of the metal sheets 102 of thisbattery have the same polarity, their peripheral portions can be joinedtogether by welding. They can be firmly joined by laser welding orultrasonic welding. Even when the peripheral portions of the metalsheets 102 are joined with an adhesive 110 a, it is possible to apply asufficient pressure thereto, thereby improving the reliability of thejoined portion. The adhesive 110 a used herein need not have insulatingproperty.

[0087] In this battery, the metal sheet 102 has the active materiallayer 103 on one surface thereof, and the other surface serves as theouter surface of the outer jacket. With such structure, it is notnecessary to separately prepare an outer jacket for covering the powergenerating elements. Thus, a thin, compact battery with high energydensity can be produced.

[0088] The outer surface of the outer electrode plate 101 may be coatedwith a resin layer for the purpose of reinforcing. For example, it iseffective to form a resin layer on the outer surface of the outerelectrode plate 101 except on its portion to be used as an externalterminal. Alternatively, a resin film may be attached on the outersurface of the outer electrode plate 101. Preferably, a portion of thebattery susceptible to damage, such as a corner portion, may bereinforced with resin.

[0089] Next, detailed descriptions are made on the method of producingthe non-aqueous electrolyte battery of Embodiment 1 in accordance withthe present invention. (i) Step (1a)

[0090] The step (1a) is the step of forming an active material layer ofa first polarity on a flat portion of one surface of a metal sheetexcept for a peripheral portion thereof, thereby producing an outerelectrode plate. FIG. 2 is an oblique view of the outer electrode plate101 produced in the step (1a) which comprises the metal sheet 102 andthe active material layer 103 formed on one surface thereof.

[0091] Metal is exposed at a peripheral portion 108 of the metal sheet102. When peripheral portions 108 facing each other are joined with anadhesive, it is preferable to: divide each of the peripheral portions108 into an exposed metal portion inside dashed lines 108 a and anexposed metal portion outside dashed lines 108 b, as shown in FIG. 3;provide the adhesive to one of the exposed metal portion 108 a and theexposed metal portion 108 b; and join another of the exposed metalportions by ultrasonic welding or laser welding. The combined use of anadhesive and welding can greatly improve the bonding strength.

[0092] There is no specific limitation on the method of providing anelectrode mixture of a first polarity on the flat portion of one surfaceof the metal sheet 102 except for the peripheral portion 108 to form theactive material layer 103. For example, it can be performed by using anyconventional coating apparatus. It is preferable that the activematerial layer 103 has a thickness of 30 to 300 μm. The peripheralportion 108 has a width of, for example, 1 to 10 mm.

[0093] As the metal sheet 102, a metal sheet having no pore is used,since it serves both as the current collector of the outer electrodeplate 101 and the outer surface of the outer jacket. Since the activematerial layer 103 formed on the inner side of the outer electrode plate101 has the effect of improving the strength of the outer jacket, a thinmetal sheet having a thickness of about 10 μm can be used. A thin metalsheet is suitable for closely attaching the active material layer toform a flexible outer electrode plate. A preferred thickness of themetal sheet 102 is 10 to 100 μm. When the metal sheet 102 is too thick,the battery thickness may be increased or the energy density of thebattery may be decreased.

[0094] In the case of using a thin metal sheet, consideration needs tobe given to corrosion of the metal sheet. From the viewpoint ofcorrosion resistance, the metal sheet 102 preferably comprises aluminumor aluminum alloy when the outer electrode plate 101 is the positiveelectrode. On the other hand, the metal sheet 102 preferably comprisescopper, iron, copper alloy or iron alloy when the outer electrode plate101 is the negative electrode. When the metal sheet 102 comprises ironor iron alloy, it is preferable to plate the surface thereof withnickel.

[0095] The positive electrode mixture is prepared, for example, bymixing a positive electrode active material, conductive agent, binder,dispersion medium and the like. The negative electrode mixture isprepared, for example, by mixing a negative electrode material, binder,dispersion medium and the like. As described above, the electrodemixture may be further added with a polymer electrolyte or a gel-formingagent.

[0096] As the positive electrode active material, any of positiveelectrode active materials commonly used in the non-aqueous electrolytebattery may be employed without any specific limitation. As the positiveelectrode active material, a lithium-containing transition metal oxide,such as LiCoO₂, LiNiO₂ or LiMn₂O₄, is preferably used. It is preferablethat the positive electrode active material has a mean particle diameterof 1 to 100 μm.

[0097] As the negative electrode material, any of negative electrodematerials commonly used in the non-aqueous electrolyte battery may beemployed without any specific limitation. As the negative electrodematerial, natural graphite or artificial graphite is preferably used. Itis preferable that the negative electrode material has a mean particlediameter of 1 to 100 μm.

[0098] As the conductive agent, carbon powder such as graphite powder orcarbon black, or carbon fiber is preferably used.

[0099] As the binder, a fluorocarbon resin, which has resistance to anon-aqueous electrolyte, is preferably used. For example,polytetrafluoroethylene, a copolymer of tetrafluoroethylene andhexafluoropropylene, polyvinylidene fluoride, a copolymer of vinylidenefluoride and hexafluoropropylene or the like is preferably used. Thesepolymers can also be used as the gel-forming agent.

[0100] As the dispersion medium, N-methyl-2-pyrrolidone is preferablyused.

[0101] (ii) Step (2a)

[0102] The step (2a) is the step of producing an electrode plate of asecond polarity 104, which is the counter electrode of the outerelectrode plate 101. The electrode plate of a second polarity 104 may beproduced by providing an electrode mixture of a second polarity on bothsurfaces of a sheet-like current collector 105 to form active materiallayers 106. There is no specific limitation on the method of providingthe electrode mixture of a second polarity on both surfaces of thesheet-like current collector 105 to form the active material layers 106.For example, it can be performed by using any conventional commoncoating apparatus. For example, a common coating apparatus is used tocontinuously apply the electrode mixture of a second polarity on bothsurfaces of a band-shaped metal sheet, followed by cutting the same. Itis preferable that the active material layer 106 has a thickness of, forexample, 30 to 300 μm.

[0103] As the sheet-like current collector 105, a metal sheet, metalmesh, punched metal, metal lath sheet or the like may be employed. Thesurface of the sheet-like current collector 105 may be roughened byetching, or may be provided with a conductive agent. When the electrodeplate of a second polarity 104 is the negative electrode, the sheet-likecurrent collector 105 preferably comprises copper, iron, copper alloy oriron alloy. When the sheet-like current collector 105 comprises iron oriron alloy, it is preferable to plate the surface thereof with nickel.When the electrode plate of a second polarity is the positive electrode,the sheet-like current collector 105 preferably comprises aluminum oraluminum alloy. It is preferable that the sheet-like current collector105 has a thickness of 10 to 100 μm.

[0104] A lead 109 is connected to the electrode plate of a secondpolarity 104. The lead 109 may be formed by utilizing a portion of thecurrent collector 105. The lead 109 is coated with the insulating resin110 b at a portion to be sandwiched between the peripheral portions 108of the metal sheets 102 which serve as the current collector of theouter electrode plate 101.

[0105] (iii) Step (3a)

[0106] The step (3a) is the step of sandwiching the electrode plate of asecond polarity 104 by a pair of the outer electrode plates 101 eachhaving the active material layer 103 disposed on the inner side thereof,with the separator layers 107 interposed therebetween. The separatorlayer 107 is formed by previously molding the separator layer 107 intothe shape of a film and disposing it between the electrode plates, or byapplying a paste comprising the starting material of the separator layer107 onto an electrode plate of one polarity and placing thereon anelectrode plate of another polarity.

[0107] The separator layer 107 may be composed only of a polymerelectrolyte, or may be a hybrid comprising a polymer electrolyte andeither a microporous membrane or non-woven fabric. As the polymerelectrolyte, conventionally known ones may be employed without anyspecific limitation. Particularly, a gel electrolyte comprising a liquidnon-aqueous electrolyte and a polymer retaining the same is preferablyused. The separator layer may contain a powder of alumina, silica or thelike. These powders perform the function of ensuring the separationbetween the electrode plates in a stacked and compressed electrode plategroup.

[0108] For example, as shown in FIG. 2 or 3, it is preferable tocompletely cover the active material layer 103 of the outer electrodeplate 101 by the separator layer 107. By sandwiching a single sheet ofthe electrode plate of a second polarity 104 by a pair of the outerelectrode plates 101 using two sheets of the separator layers 107, andcompressing the whole while heating, an electrode plate group as shownin FIG. 4 is produced, in which all the electrode plates and separatorlayers are integrated. The heating temperature used herein is preferably80 to 160° C. When a thermoplastic resin is provided, as an adhesive, atthe peripheral portion 108 of the metal sheet 102 constituting the outerelectrode plate 101, prior to compressing the electrode plate group, itis possible to join the peripheral portions 108, simultaneously with thecompressing.

[0109] As the liquid non-aqueous electrolyte, a non-aqueous solventcontaining a solute dissolved therein is preferably used. As the solute,lithium salts, such as LiPF₆ and LiBF₄ are preferable. As thenon-aqueous solvent, ethylene carbonate, dimethyl carbonate, ethylmethyl carbonate, propylene carbonate, diethyl carbonate and the likeare employed. These may be used alone or in combination.

[0110] As the polymer or gel-forming agent retaining the liquidnon-aqueous electrolyte, a polymer which can be cross-linked by UVirradiation or heating, is preferably used. When the polymer orgel-forming agent is cross-linked after forming the electrode plategroup, a polymer which can be cross-linked by heating is particularlypreferable. When the separator layer 107 is formed on the activematerial, as shown in FIG. 3, a polymer which can be cross-linked by UVirradiation may also be employed.

[0111] Examples of the preferable gel-forming agent include fluorocarbonresins having resistance to a non-aqueous electrolyte. Amongfluorocarbon resins, polyvinylidene fluoride, a copolymer of vinylidenefluoride and hexafluoropropylene and the like are particularlypreferable. A mixture of each of these polymers with a solvent such asN-methyl-2-pyrrolidone is suitably used as the paste comprising thestarting material of the separator layer, because the viscosity thereofcan be freely adjusted.

[0112] The paste comprising the starting material of the separator layermay be added with an oil component such as dibutyl phthalate. In thiscase, the oil component is extracted or removed with a solvent such asether, hexane or acetone, after forming the separator layer. As aresult, a large number of micropores are formed in the separator layer.Such a separator layer quickly absorbs the liquid non-aqueouselectrolyte even within a thin electrode plate group, therebyeffectively promoting the gelation.

[0113] (iv) Step (4a)

[0114] The step (4a) is the step of joining the peripheral portions 108of the metal sheets 102 constituting the outer electrode plates 101facing each other. The joining is performed, for example, by laserwelding, ultrasonic welding or by means of an adhesive.

[0115] Ultrasonic welding or laser welding allows a direct joining ofthe peripheral portions of the metal sheets, thereby making it possibleto reduce the space of the peripheral portions required for the joining,compared with the case where an adhesive is used.

[0116] Additionally, as described above, it is also possible to: divideeach of the peripheral portions 108 into an exposed metal portion 108 ainside dashed lines and the exposed metal portion 108 b outside dashedlines, as shown in FIG. 3; provide the adhesive to one of the exposedmetal portion 108 a and the exposed metal portion 108 b; and joinanother of the exposed metal portions by ultrasonic welding or laserwelding.

[0117] As the adhesive, a thermosetting resin such as an epoxy resin ora thermoplastic resin such as polyolefin may be employed. The latter issuperior in workability. Among thermoplastic resins, polyethylene andpolypropylene are suitable because they have a high melting point.

[0118] In the case of injecting the liquid non-aqueous electrolyte intothe battery after the joining, an unjoined region is reserved betweenthe peripheral portions 108 facing each other, instead of completelyjoining them. Then, the non-aqueous electrolyte is injected from theunjoined region after the step (4a).

[0119] Embodiment 2

[0120] In general, a polymer electrolyte contains a flammablenon-aqueous solvent. In case the battery is short-circuited or itscharging circuit breaks down, the battery may be subjected toovercharging with a large current for a long time. In such a case, owingto an abnormally increased battery temperature, the non-aqueouselectrolyte is decomposed to generate a flammable gas, resulting in theswelling of the battery or the degradation in the battery function. Inorder to obviate this, an overcurrent breaking device is connected to acircuit of equipment in which the battery is installed. As theovercurrent breaking device, a thermal fuse or a device (hereinafter,referred to as “PTC devices”) having a positive temperature resistancecoefficient is preferably used, for example. Because its resistanceincreases with an increase in temperature, the PTC device serves tobreak or reduce a current at elevated temperatures.

[0121]FIG. 5 is a vertical sectional view showing a main part of anon-aqueous electrolyte battery of Embodiment 2 in accordance with thepresent invention, which is provided with a PTC device 112. Componentshaving similar structures or compositions to those of Embodiment 1 arenumbered with the same numbers as those of Embodiment 1.

[0122] The PTC device 112 is disposed on a lead 109 sandwiched betweenthe peripheral portions of outer electrode plates 101, in the state ofbeing sealed with an insulating resin 110 b. The insulating resin 110 bpreferably has resistance to a non-aqueous electrolyte.

[0123] In the above-described configuration, since the PTC device 112and the battery are integrated with each other, a temperature change inthe battery can be sensitively transmitted to the PTC device 112,thereby effectively preventing an abnormal temperature increase.

[0124] Embodiment 3

[0125] In the step (1a), as shown in FIG. 6, it is effective tointermittently form a plurality of active material layers of a firstpolarity 103 on the flat portion of one surface of a band-shaped metalsheet 202 except for the peripheral portion thereof, thereby producingan outer electrode plate assembly comprising a plurality of outerelectrode plate units 201 aligned in a row. Intermittently forming aplurality of the active material layers of a first polarity 103 resultsin an exposed metal portion (peripheral portion) 208 reserved aroundeach of the active material layers 103.

[0126] While the outer electrode plate assembly may be used after beingseparated into individual outer electrode plate units 201, using theouter electrode plate assembly as it is allows a series of the steps tobe continuously performed, thereby making it possible to produce thebattery efficiently. More specifically, in the step (3a), a pair ofouter electrode plate assemblies is prepared, and a separator layer 107is formed on each of the active material layers 103 of each of the outerelectrode plate assemblies as shown in FIG. 7.

[0127] Subsequently, as shown in FIG. 8, each of the electrode plateunits of one of the outer electrode plate assemblies and each of theouter electrode plate units of the other outer electrode plate assembly,are successively disposed so as to face each other, with the activematerial layers 103 thereof disposed facing inwardly, and the electrodeplate of a second polarity 104 is successively sandwiched by a pair ofthe outer electrode plate units facing each other, with the separatorlayer 107 interposed therebetween.

[0128] The electrode plate of a second polarity 104 is formed byproviding an active material layer of a second polarity 106 on bothsurfaces of a sheet-like current collector 105, and the lead 109 coatedwith the insulating resin 110 b is connected to the sheet-like currentcollector 105. As a result, an electrode plate group assembly as shownin FIG. 9 is produced.

[0129] Alternatively, when an adhesive 110 a is previously provided atthe peripheral portion 208 of the outer electrode plate unit 201 in thestep (1a), a battery assembly as shown in FIG. 10 can be produced in thestep (3a). The battery assembly may be either used as it is, or usedafter being separated.

[0130] It is also possible to use one of the outer electrode plates inthe form of an assembly, and use the other after separating it. In thiscase, the step (3a) gives an electrode plate group assembly as shown inFIG. 11.

[0131] It should be noted that each component of the non-aqueouselectrolyte battery of Embodiment 3 has the same structure orcomposition as those of Embodiment 1, except that the metal sheet 202constituting the outer electrode plate is originally band-shaped. InFIGS. 6 to 12, components having similar structures or compositions tothose of Embodiment 1 are numbered with the same numbers as those ofEmbodiment 1.

[0132] Embodiment 4

[0133]FIG. 12 shows a vertical sectional view of a non-aqueouselectrolyte battery of Embodiment 4 in accordance with the presentinvention. This battery is a non-aqueous electrolyte battery in adouble-stacked form, which further comprises: an additional electrodeplate of a first polarity 110 a disposed adjacent to the electrode plateof a second polarity 104, with a separator layer 107 interposedtherebetween; and an additional electrode plate of a second polarity 104disposed adjacent to the additional electrode plate of a first polarity110 a, with a separator layer 107 interposed therebetween.

[0134] Although the battery in a double-stacked form is shown herein,any number of the electrode plates of a second polarity 104 may besandwiched by the outer electrode plates of a first polarity 101.

[0135] When a battery has two or more electrode plates of a secondpolarity 104 as in this case, an additional electrode plate of a firstpolarity is interposed between the electrode plates of a secondpolarity. With this structure, it is possible to increase the batterycapacity by appropriately selecting the number of the electrode platesand the thickness of the active material layer, without degrading thehigh-rate discharge characteristic. Therefore, increasing the batterycapacity does not excessively increase the battery area, or increase thethickness of the active material layer so that the active materialutilization or high-rate discharge characteristic will not be reduced.

[0136] In the case of FIG. 12, two current collectors 105 of theelectrode plates of a second polarity 104 are connected to a single lead109 which penetrates through an insulating resin 110 b to be drawn tothe outside from within the battery. On the other hand, a currentcollector 102 a of the additional electrode plate of a first polarity101 a having the same polarity as the outer electrode plate 101, isconnected to the outer electrode plates 101, in the state of beingsandwiched between the peripheral portions of the metal sheets 102, andis drawn to the outside from within the battery to serve as a lead 111.

[0137] As the current collector 102 a of the additional electrode plateof a first polarity 101 a, a metal sheet, metal mesh, punched metal,metal lath sheet and the like may be employed. The surface of thecurrent collector 102 a may be roughened by etching, or may be providedwith a conductive agent. When the additional electrode plate of a firstpolarity 101 a is the negative electrode, the current collector 102 apreferably comprises copper, iron, copper alloy or iron alloy. When thecurrent collector 10aa comprises iron or iron alloy, it is preferable toplate the surface thereof with nickel. When the additional electrodeplate of a first polarity 101 a is the positive electrode, the currentcollector 102 a preferably comprises aluminum or aluminum alloy. It ispreferable that the current collector 102 a has a thickness of 10 to 100μM.

[0138] The battery of Embodiment 4 can be produced in the same manner asin the case of the batteries of Embodiments 1 to 3, except that, in thestep (3a), in place of a single sheet of the electrode plate of a secondpolarity, a pair of electrode plates of a second polarity sandwiching anadditional electrode plate of a first polarity with a separator layerinterposed therebetween, is used to produce an electrode plate group asshown in FIG. 13.

[0139] It should be noted that the non-aqueous electrolyte battery ofEmbodiment 4 has the same structure or composition as that of Embodiment1, except that it has two sheets of electrode plates of a secondpolarity and an additional electrode plate of a first polarity. In FIGS.12 to 13, components having similar structures or compositions to thoseof Embodiment 1 are numbered with the same numbers as those ofEmbodiment 1.

[0140] Embodiment 5

[0141]FIG. 14 shows a plane view of a non-aqueous electrolyte battery ofEmbodiment 5 in accordance with the present invention. Further, FIG. 15,FIG. 16 and FIG. 17 show examples of sectional views taken on lines I-I,II-II and III-III in FIG. 14, respectively.

[0142] This battery has the same structure as the battery of Embodiment1, except that the outer jacket serving also as the current collector ofan outer electrode plate 301, comprises a single metal sheet folded soas to have two flat portions facing each other. In FIGS. 14 to 17,components having similar structures or compositions to those ofEmbodiment 1 are numbered with the same numbers as those of Embodiment1.

[0143] Accommodated inside an outer electrode plate 301 comprising ametal sheet 302 and active material layers of a first polarity 103formed on one surface thereof, is an electrode plate of a secondpolarity 104 comprising a current collector 105 and active materiallayers of a second polarity 106 formed on both surfaces thereof, with aseparator layer 107 interposed therebetween. The peripheral portions ofthe metal sheet 302 serving as the current collector of the outerelectrode plate 301 are joined with an adhesive 110 a. A lead 109 isconnected to the current collector 105 of the electrode plate of asecond polarity 104, and the lead 109 is coated with an insulating resin110 b at a part thereof sandwiched between the peripheral portions 308of the metal sheet 302.

[0144] As shown in FIG. 16, a lead 111 is directly connected to themetal sheet 302 serving as the current collector of the outer electrodeplate 301. While the lead 111 may be connected to any part of the metalsheet 302, it is sandwiched between the peripheral portions 308 of themetal sheet 302 in FIG. 16.

[0145] In the case of the battery of Embodiment 5, since the metal sheet302 serving also as the outer jacket is folded so as to have two flatportions facing each other, a crease line 113 is formed as shown in FIG.17.

[0146] With this structure, it is not necessary to provide any space forthe joining at the part of the metal sheet corresponding to the creaseline 113, so that the battery area is reduced by such space. It is alsopossible to simplify the joining step of the peripheral portions of themetal sheet 302.

[0147] Next, detailed descriptions are made on the method of producingthe non-aqueous electrolyte battery of Embodiment 5 in accordance withthe present invention.

[0148] (i) Step (1b)

[0149] The step (1b) is the step of preparing a metal sheet providedwith a crease line or an imaginary crease line to be folded so as tohave two flat portions facing each other. As this metal sheet, a metalsheet similar to the one used for the outer electrode plate inEmbodiment 1 may be used. More specifically, a metal sheet having ashape in which two pieces of the metal sheets used for the outerelectrode plate of Embodiment 1 are connected, is prepared and a creaseline or imaginary crease line is positioned at the center thereof. It ispreferable to previously provide the metal sheet with a crease line.

[0150] (ii) Step (2b)

[0151] The step (2b) is the step of forming a pair of active materiallayers of a first polarity on the flat portions, symmetrical withrespect to the crease line or imaginary crease line, of one surface ofthe metal sheet except for peripheral portions thereof, therebyproducing an outer electrode plate.

[0152] The method of applying the electrode mixture to the metal sheetis not specifically limited, and can be performed by using anyconventional common coating apparatus. It is preferable that the activematerial layer has a thickness of, for example, 30 to 300 μm. It ispreferable that the peripheral portion of the metal sheet to be reservedfor the joining has a width of 1 to 10 mm.

[0153] (iii) Step (3b)

[0154] The step (3b) is the step of producing an electrode plate of asecond polarity. The electrode plate of a second polarity can beproduced in the same manner as in the case of the electrode plate of asecond polarity of Embodiment 1.

[0155] (iv) Step (4b)

[0156] The step (4b) is the step of folding the outer electrode plate atthe crease line or imaginary crease line to sandwich the electrode plateof a second polarity by the pair of active material layers of a firstpolarity with separator layers interposed therebetween.

[0157]FIG. 18 shows an uncompleted non-aqueous electrolyte battery withan outer electrode plate thereof bent halfway in the step (4b). In FIG.18, the outer electrode plate 301 has two active material layers of afirst polarity 103 respectively at the positions, symmetrical withrespect to the crease line 113, of the inner surface thereof. Theperipheral portions 308, which are exposed metal portions, are reservedas a region for the joining, around the active material layers 103.Although not shown herein, when the peripheral portions 308 are joinedwith an adhesive, it is preferable to provide an adhesive for thejoining to the four sides of the peripheral portions 308, except for thesides corresponding to the crease line 113. When the peripheral portions308 are joined by welding, the adhesive may not be necessarily provided.

[0158] A separator layer 107 is disposed on each of the active materiallayers of a first polarity 103, and an electrode plate of a secondpolarity 104 provided with a lead 109 is placed on one of the separatorlayers 107. The lead 109 is coated with an insulating resin 110 b at aportion thereof to be sandwiched between the peripheral portions 308 ofa metal sheet 302. Further, one end of a lead 111 of the outer electrodeplate is placed on the peripheral portion 308 of the metal sheet 302.

[0159] By completely folding the outer electrode plate 301 at the creaseline 113 in the above-described arrangement, an electrode plate group isformed. In order to improve the accuracy of the operations and theworkability, it is preferable to previously provide the metal sheet 302with the crease line 113, instead of folding the metal sheet 302 at theimaginary crease line.

[0160] After being stacked, the electrode plate group is compressed tocause the components to sufficiently adhere together so that they areintegrated. When the separator layer or the active material layercontains, as a gel-forming agent, a thermally-crosslinking polymer whichis the starting material of the polymer electrolyte, it is preferable tocompress the electrode plate group at a temperature at which thegel-forming agent is crosslinked, thereby simultaneously promoting theformation of the polymer electrolyte and the integration of theelectrode plate group. As such a temperature, a temperature of 80 to130° C. is suitable.

[0161] (v) Step (5b)

[0162] The step (5b) is the step of joining the peripheral portions ofthe outer electrode plate facing each other. This step can be performedin the same manner as in the step (4a) of Embodiment 1.

[0163] Embodiment 6

[0164] In order to efficiently produce the battery, it is effectivethat, in the step (1b), a band-shaped metal sheet 402 is prepared, whichis provided with a crease line (or an imaginary crease line) 113parallel with a longitudinal direction, and in the step (2b), pluralpairs of active material layers of a first polarity 103 areintermittently formed on the flat portions, symmetrical to the creaseline 113, of one surface of the band-shaped metal sheet 402 except forthe peripheral portions thereof, thereby producing an outer electrodeplate assembly comprising a plurality of outer electrode plate units 401aligned in a row. Further, it is effective that, in the step (4b), theelectrode plate of a second polarity 104 is successively sandwiched by apair of active material layers 103 of each outer electrode plate unit,with the separator layers 107 interposed therebetween.

[0165] In order to efficiently produce the battery, it is also effectivethat, in the step (4b), a paste comprising the starting material of theseparator layer is applied on the active material layer of a firstpolarity 103 or the electrode plate of a second polarity 104, therebyforming the separator layer 107. The paste comprising the startingmaterial of the separator layer preferably contains a gel-forming agentand either a solvent or a liquid non-aqueous electrolyte.

[0166] In FIG. 19, the production process of the non-aqueous electrolytebattery proceeds in the direction shown by the arrow.

[0167] Firstly, the active material layers of a first polarity 103 aresuccessively formed on the positions, symmetrical with respect to acrease line 113, of the band-shaped metal sheet. Herein, wherenecessary, an adhesive for the joining or a lead 111 for the electrodeplate of a first polarity is disposed around the active material layer103, that is, the a peripheral portion 408 of an electrode plate of afirst polarity.

[0168] Subsequently, a separator layer 107 is provided so as to coverthe surface of each of the active material layers 103. While a separatorpreviously molded in a sheet-shape may be placed on the active materiallayer, it is more efficient to successively apply, onto the activematerial layer, a paste comprising the starting material of theseparator layer, in the case of a continuous manufacturing process.

[0169] Then, an electrode plate of a second polarity 104 is placed onthe separator layer 107. A lead 109 previously coated with an insulatingresin 110 b is connected to the electrode plate of a second polarity104.

[0170] Next, positions to be cut 114 of the band-shaped metal sheet arepartly cut off, from its junction with the crease line 113 through oneend of the metal sheet. Then, the outer electrode plate is bent at thecrease line 113 to place one of the active material layers 103 on theelectrode plate of a second polarity 104. While the outer electrodeplate can be bent without partly cutting off the positions to be cut114, it is more preferable to partly cut off the same from theviewpoints of workability and reliability. Subsequently, pressure isapplied to the electrode plate group from top and bottom.

[0171] While the peripheral portions of the outer electrode platesfacing each other can be joined after cutting off the electrode plategroup, it is preferable to produce a battery assembly by performing thejoining without conducting the cutting off. Then, it is preferable tocut off each battery after the battery assembly has been completed.

[0172] Embodiment 7

[0173] The non-aqueous electrolyte battery of Embodiment 7 in accordancewith the present invention has the same structure as that of the batteryof Embodiment 4, except that the outer jacket serving also as thecurrent collector of the outer electrode plate comprises a single metalsheet folded so as to have two flat portions facing each other. The topplane view of the non-aqueous electrolyte battery of the Embodiment 7 issimilar to that of the non-aqueous electrolyte battery of Embodiment 5in accordance with the present invention and can be shown in FIG. 14.

[0174]FIG. 20, FIG. 21 and FIG. 22 show examples of the sectional viewsof the battery of Embodiment 7 which have a top plane view shown in FIG.14, taken on lines I-I, II-II, and III-III, respectively. In FIGS. 20 to22, components having similar structures or compositions to those ofEmbodiment 4 or Embodiment 5 are numbered with the same numbers as thoseof Embodiment 4 or Embodiment 5.

[0175] More specifically, this battery further comprises an additionalelectrode plate of a first polarity 110 a disposed adjacent to theelectrode plate of a second polarity 104, with a separator layer 107interposed therebetween; and an additional electrode plate of a secondpolarity 104 disposed adjacent to the additional electrode plate of afirst polarity 110 a, with a separator layer 107 interposedtherebetween. Although the battery comprising two stacks was shownherein, any number of the electrode plate of a second polarity 104 maybe sandwiched by the outer electrode plates of a first polarity 301.

[0176] In the following, the present invention is concretely describedin detail by referring to examples. It should be noted that each batterydescribed herein is of a flat type of about 10 cm length by 10 cm width.

EXAMPLE 1

[0177] In this example, a battery in a single-stacked form as shown inFIG. 1 was fabricated, in which an outer electrode plate serves as apositive electrode.

[0178] (i) Production of Outer Electrode Plate

[0179] LiCoO₂ as a positive electrode active material, carbon powder asa conductive agent, a gel-forming agent, which also served as a binder,and N-methyl-2-pyrrolidone were mixed to give a positive electrodemixture. As the gel-forming agent, a copolymer (hereinafter, referred toas P(VDF-HFP)) comprising 90 wt % of vinylidene fluoride units and 10 wt% of hexafluoropropylene units was used. N-methyl-2-pyrrolidone was usedin the ratio of 70 parts by weight with respect to 100 parts by weightof P(VDF-HFP). The weight ratio of the active material: the conductiveagent: P(VDF-HFP) was set to be 100:5:8.

[0180] A band-shaped, film-type, aluminum current collector having awidth of 150 mm and a thickness of 30 μm, was used as a metal sheet. Asshown in FIG. 6, at the center of one surface thereof, the positiveelectrode mixture was intermittently applied in a thickness of 120 μm tosuccessively form a plurality of positive electrode active materiallayers in the shape of a square of 86×86 mm, thereby producing an outerelectrode plate assembly. A spacing of about 17 mm was provided betweenthe positive electrode active material layers.

[0181] (ii) Production of Negative Electrode

[0182] Graphite powder as a negative electrode material, carbon black asa conductive agent, P(VDF-HFP) and N-methyl-2-pyrrolidone were mixed togive a negative electrode mixture. The weight ratio of the activematerial: the conductive agent: P(VDF-HFP) was set to be 100:8:14.N-methyl-2-pyrrolidone was used in the ratio of 70 parts by weight withrespect to 100 parts by weight of P(VDF-HFP).

[0183] A band-shaped, film-type, copper current collector having a widthof 150 mm and a thickness of 10 μm, was employed. On both surfacesthereof, the negative electrode mixture was respectively applied in athickness of 125 μm to form negative electrode active material layers,thereby producing a band-shaped negative electrode plate. From thisnegative electrode plate, a plurality of negative electrodes in theshape of a square of 88×88 mm were cut out. A nickel lead was connectedto the current collector of the negative electrode. The lead was coatedwith an insulating resin in a part thereof sandwiched between theperipheral portions of the outer electrode plates.

[0184] (iii) Production of Electrode Plate Group

[0185] As shown in FIG. 7, a separator layer 7 comprising P(VDF-HFP) wasformed on each of the positive electrode active material layers of theouter electrode plate assembly. Specifically, the positive electrodeactive material layer was completely coated with a paste comprisingP(VDF-HFP) mixed with N-methyl-2-pyrrolidone and was dried to form aseparator layer in the shape of a square of 89×89 mm, having a thicknessof about 25 μm.

[0186] Next, from the outer electrode plate assembly having a width of150 mm, the end portions were cut away so as to leave a peripheralportion composed of an exposed metal portion having a width of 7 mm. Theperipheral portion of each of the outer electrode plate units wasdivided into an inner exposed metal portion and an outer exposed metalportion, and a polypropylene film having a thickness of 40 μm, wasdisposed on the inner one, as an adhesive.

[0187] As shown in FIG. 8, a pair of outer electrode plate units wassuccessively disposed such that their positive electrode active materiallayers faced each other, and a single sheet of the negative electrodewas sandwiched by the pair of outer electrode plate units. The electrodeplate group thus stacked was successively heated under a pressure of 60gf/cm² until the surface temperature thereof reached 120° C., andintegrated so as to be flattened, thereby forming an electrode plategroup assembly as shown in FIG. 9.

[0188] (iv) Joining of Peripheral Portions

[0189] The peripheral portions of the electrode plate group assemblywere pressed for three seconds at 220±5° C. under 10 kgf/cm², and joinedby melting the polypropylene film interposed between the peripheralportions. However, an unjoined region was reserved for injecting anon-aqueous electrolyte. From the unjoined region, a non-aqueouselectrolyte was injected under reduced pressure, and heated to 60° C. orhigher to cause the gelation of P(VDF-HFP) in the electrode plate andseparator layer.

[0190] The above non-aqueous electrolyte was prepared by dissolvingLiPF₆ at a concentration of 1 mol/L in a mixed solvent of ethylenecarbonate and diethyl carbonate with a volume ratio of 1:1.

[0191] Thereafter, the pressure inside the battery was reduced and theunjoined region was sealed. This gave an assembly of Batteries B havinga completely sealed structure as shown in FIG. 10. The assembly ofBatteries B was separated at the end of the process.

Comparative Example 1

[0192] The electrode plate group assembly produced in Example 1 wasseparated into individual electrode plate groups, each of which werethen covered by an outer jacket with a thickness of 150 μm comprising analuminum foil and polypropylene layers on both surfaces thereof.Subsequently, a non-aqueous electrolyte was injected into the outerjacket and heated to 60° C. or higher to cause the gelation ofP(VDF-HFP) in the electrode plate and separator layer, followed bysealing the outer jacket. Since the outer electrode plate was alsoenclosed in the outer jacket by this step, a positive electrode lead wasalso connected to the outer electrode plate, and the positive electrodelead and the negative electrode lead were drawn from the outer jacket tothe outside. This gave Battery A having a sealed structure, which wasthe equivalent of a conventional product.

EXAMPLE 2

[0193] Battery C having a sealed structure was produced in the samemanner as in the case of Battery B of Example 1, except that a resinlayer comprising polypropylene with a thickness of 50 μm was laminatedon an outer surface of the current collector of the outer electrodeplate.

EXAMPLE 3

[0194] In this example, a battery in a double-stacked form as shown inFIG. 12 was produced, in which the positive electrode served as theouter electrode plate.

[0195] (i) Production of Additional Positive Electrode

[0196] The same positive electrode mixture as used for the outerelectrode plate was applied on both surfaces of a band-shaped, film-typecurrent collector made of aluminum with a width of 150 mm and athickness of 30 μm to form active material layers having a thickness of120 μm respectively on both surfaces of the current collector. From theband-shaped electrode plate thus obtained, an additional positiveelectrode in the shape of a square of 86×86 mm, provided with a lead,was punched out.

[0197] (ii) Production of Electrode Plate Group

[0198] A paste comprising P(VDF-HFP) mixed with N-methyl-2-pyrrolidonewas applied on both surfaces of the additional positive electrode so asto completely cover the positive electrode mixture, and the whole wasdried to form a separator layer having a thickness of about 25 μm. Theobtained additional positive electrode having the separator layers onboth surfaces thereof was sandwiched by two negative electrodes producedin Example 1.

[0199] On the other hand, two outer electrode plate assemblies producedin Example 1 were prepared, each outer electrode plate unit of one ofthe outer electrode plate assemblies and each outer electrode plate unitof the other outer electrode plate assembly were successively disposedsuch that their positive electrode active material layers faced eachother, and the above additional positive electrode sandwiched by the twonegative electrodes was sandwiched by a pair of the outer electrodeplate units. Then, the thus stacked electrode plate group was heatedunder a pressure of 60 gf/cm² 2 until the surface temperature thereofreached 120° C., and integrated so as to be flattened, thereby producingan electrode plate group assembly.

[0200] (iii) Joining of Peripheral Portions

[0201] The peripheral portions were joined in the same manner as in thecase of Battery B, except that the lead of the additional positiveelectrode was interposed between the peripheral portions of the outerelectrode plates and was electrically connected to the outer electrodeplate, thereby producing Battery D having a sealed structure.

EXAMPLE 4

[0202] In the production step of the outer electrode plate, a spacing ofabout 9 mm was provided between the positive electrode active materiallayers, and the end portions of the outer electrode plate assemblyhaving a width of 150 mm was cut away so as to reserve a peripheralportion composed of an exposed metal portion having a width of 3 mm.Then, the peripheral portions facing each other of the outer electrodeplates were joined by ultrasonic welding, instead of joining them by anadhesive. Except for the above, Battery E having a sealed structure wasproduced in the same manner as in the case of Battery B of Example 1.The reason why the width of the peripheral portion to serve as thejoined part was reduced to 3 mm was that ultrasonic welding could yieldhigh bonding strength.

EXAMPLE 5

[0203] In the production step of the outer electrode plate, a spacing ofabout 7 mm was provided between the positive electrode active materiallayers, and the end portions of the outer electrode plate assemblyhaving a width of 150 mm was cut away so as to reserve a peripheralportion composed of an exposed metal portion having a width of 2 mm.Then, the peripheral portions facing each other of the outer electrodeplates were joined by laser welding, instead of joining them with anadhesive. Except for the above, Battery F having a sealed structure wasproduced in the same manner as in the case of Battery B of Example 1.The reason why the width of the peripheral portion to serve as thejoined part was reduced to 2 mm was that laser welding could yield ahigher bonding strength than ultrasonic welding.

EXAMPLE 6

[0204] Battery G was produced in the same manner as in the case ofBattery B, except that the outer exposed metal portions of theperipheral portions of the outer electrode plates, where thepolypropylene film was not disposed, were joined by laser welding. Inthe case of Battery G, since the inner exposed metal portions of theperipheral portions were joined by an adhesive and the outer exposedmetal portions of the peripheral portions were joined by laser welding,the bonding reliability was improved as compared with Battery B.

EXAMPLE 7

[0205] Battery H was produced in the same manner as in the case ofBattery B, except that the outer exposed metal portions of theperipheral portions of the outer electrode plates, where thepolypropylene film was not disposed, were joined by ultrasonic welding.In the case of Battery H, since the inner exposed metal portions of theperipheral portions were joined by an adhesive and the outer exposedmetal portions of the peripheral portions were joined by ultrasonicwelding, the bonding reliability was improved as compared with that ofBattery B.

EXAMPLE 8

[0206] A PTC device having a current breaking temperature of 150° C. wasconnected to the negative electrode lead which was drawn outside fromwithin the battery. The PTC device was sealed with an insulating resinhaving resistance to the non-aqueous electrolyte, and sandwiched betweenthe peripheral portions of the outer electrode plates. Except for theabove, Battery I having a sealed structure was produced in the samemanner as in the case of Battery B of Example 1.

[0207] TABLE 1 shows the general structure, the thickness and energydensity of the above-described Batteries A to I. TABLE 1 Resin layer onouter surface of outer Battery electrode Number of thickness Energydensity Battery plate stack (mm) (Wh/l) A Present 1 0.9 267 B Notpresent 1 0.6 400 C Present 1 0.7 343 D Not present 2 1.2 400 E Notpresent 1 0.6 430 F Not present 1 0.6 440 G Not present 1 0.6 400 H Notpresent 1 0.6 400 I Not present 1 0.6 390

[0208] The weight reduction rate, capacity retention rate after storageand capacity retention rate after cycles of Batteries A to I weremeasured in the following manner.

[0209] (Weight Reduction Rate)

[0210] The battery was charged at 20° C. with a current of 1 C until thebattery voltage reached 4.2 V, and thereafter, the charging wascontinued at a constant voltage until the current reached 0.05 C.Subsequently, the battery at a charged state was stored at 60° C. for1000 hours. Then, the ratio of the amount of the weight reduction afterstorage to the weight before storage was determined in percentage. Theresults are shown in TABLE 2.

[0211] (Capacity Retention Rate After Storage)

[0212] After being measured for the weight reduction rate, the batterywas discharged at 20° C. with a current of 0.2 C. Then, the ratio of thedischarge capacity of the battery after storage to the dischargecapacity of the battery before storage was determined in percentage. Theresults are shown in TABLE 2.

[0213] (Capacity Retention Rate After Cycles)

[0214] The battery was charged at 20° C. with a current of 1 C until thebattery voltage reached 4.2 V, and thereafter, the charging wascontinued at a constant voltage until the current reached 0.05 C.Subsequently, the battery at a charged state was discharged at 20° C.with a current of 1 C until the battery voltage reached 3 V. Thisoperation was repeated 500 times. Then, the ratio of the dischargecapacity at the 500th cycle to the discharge capacity at the first cyclewas determined in percentage. The results are shown in TABLE 2. TABLE 2Capacity retention Capacity retention Weight reduction rate afterstorage rate after cycles Battery rate (%) (%) (%) A 0.2 85 85 B 0.2 8585 C 0.2 85 85 D 0.2 85 85 E 0.1 90 87 F 0.1 90 87 G 0.1 90 88 H 0.1 9087 I 0.2 85 85

[0215] As shown in TABLES 1 and 2, each of the batteries of the presentinvention has a high energy density, and also exhibits a capacityretention rate after storage and capacity retention rate after cycleswhich are comparable to or higher than those of the conventional ones.Moreover, it is shown that each of the batteries in which the peripheralportions were joined by welding has a low weight reduction rate andtherefore, has high air-tightness. This means that the non-aqueouselectrolyte batteries in accordance with the present invention have beenremarkably improved in reliability as compared with the conventionalones.

EXAMPLE 9

[0216] Battery J having a sealed structure was produced in the samemanner as in the case of Battery B of Example 1, except that theperipheral portions of the outer electrode plates were joined by beingpressed for three seconds at 220±5° C. and 5 kgf/cm².

EXAMPLE 10

[0217] Battery K having a sealed structure was produced in the samemanner as in the case of Battery B of Example 1, except that theperipheral portions of the outer electrode plates were joined by beingpressed for three seconds at 220±5° C. under 15 kgf/cm².

EXAMPLE 11

[0218] Battery L having a sealed structure was produced in the samemanner as in the case of Battery B of Example 1, except that theperipheral portions of the outer electrode plates were joined by beingpressed for three seconds at 220±5° C. under 20 kgf/cm².

[0219] The weight reduction rate, capacity retention rate after storageand capacity retention rate after cycles of the Batteries J to L weremeasured in the same manner as described above. The results are shown inTABLE 3. TABLE 3 Capacity Capacity Weight retention rate retention ratePressure reduction rate after storage after cycles Battery (Kgf/m²) (%)(%) (%) B 10 0.2 85 85 J  5 0.5 50 30 K 15 0.2 85 85 L 20 0.35 70 65

[0220] In TABLE 3, Battery J, in which the pressure applied to theperipheral portions of the outer electrode plates is as low as 5 kgf/cm², has a high weight reduction rate, and it also has significantlylow capacity retention rate after storage and capacity retention rateafter cycles. On the other hand, the performance of the battery isremarkably improved, when the pressure applied to the peripheralportions of the outer electrode plates is sufficient, i.e., 10 to 15kgf/cm². This demonstrates that the battery structure of the presentinvention has an advantage that the outer electrode plates of the samepolarity can be joined together. In other words, in the case of thebattery of the present invention in which a minor short circuit is nevercaused by the joining of the peripheral portions of the outer electrodeplates, a sufficient pressure can be applied to the joined portion,thereby markedly improving the reliability of the battery.

[0221] It should be noted that the battery performance is poor forBattery L in which the pressure applied to the peripheral portions is 20kgf/cm². The reason is presumably that the excessively high pressurecaused a melt of the polypropylene film to extrude to the outside andthus reduced the reliability of the joined portion.

EXAMPLE 12

[0222] Battery M having a sealed structure was produced in the samemanner as in the case of Battery B of Example 1, except that thepositive electrode active material layer had a thickness of 60 μm andthe negative electrode active material layer had a thickness of 65 μm.

EXAMPLE 13

[0223] Battery N having a sealed structure was produced in the samemanner as in the case of Battery B of Example 1, except that thepositive electrode active material layer had a thickness of 270 μm andthe negative electrode active material layer had a thickness of 255 μm.

[0224] The discharge characteristics of Batteries B, M and N weremeasured in the following manner.

[0225] (2 C/0.2 ratio)

[0226] The battery was charged at 20° C. with a current of 1 C until thebattery voltage reached 4.2 V, and thereafter, the charging wascontinued at a constant voltage until the current reached 0.05 C.Subsequently, the battery at a charged state was discharged at 20° C.with a current of 2 C until the battery voltage reached 3 V.

[0227] Then, the battery was charged again at 20° C. with a current of 1C until the battery voltage reached 4.2 V, and thereafter, the chargingwas continued at a constant voltage until the current reached 0.05 C.Subsequently, the battery at a charged state was discharged at 20° C.with a current of 0.2 C until the battery voltage reached 3 V.

[0228] The ratio of the discharge capacity obtained by the dischargingwith a current of 2 C to the discharge capacity obtained by thedischarging with a current of 0.2 C was determined in percentage. Theresults are shown in TABLE 4.

[0229] (1C/0.2 ratio)

[0230] The battery was charged at 20° C. with a current of 1 C until thebattery voltage reached 4.2 V, and thereafter, the charging wascontinued at a constant voltage until the current reached 0.05 C.Subsequently, the battery at a charged state was discharged at 20° C.with a current of 1 C until the battery voltage reached 3 V.

[0231] Then, the battery was charged again at 20° C. with a current of 1C until the battery voltage reached 4.2 V, and thereafter, the chargingwas continued at a constant voltage until the current reached 0.05 C.Subsequently, the battery at a charged state was discharged at 20° C.with a current of 0.2 C until the battery voltage reached 3 V.

[0232] The ratio of the discharge capacity obtained by the dischargingwith a current of 1 C to the discharge capacity obtained by thedischarging with a current of 0.2 C was determined in percentage. Theresults are shown in TABLE 4. TABLE 4 Thickness Thickness of positive ofnegative electrode electrode Capacity active active retention materialmaterial 2C/0.2C 1C/0.2C rate after Battery layer (μm) layer (μm) ratio(%) ratio (%) cycles (%) B 120 125 90 98 85 M  60  65 96 99 90 N 270 25540 70 20

[0233] TABLE 4 shows that the discharge characteristic, in particular,the high-rate discharge characteristic, decreases with an increase inthe thickness of the active material layer. As the means for increasingthe discharge capacity of thin batteries, a method has hitherto beenadopted, which involves increasing the thickness of the active materiallayer; however, as shown by the results in TABLE 4, the high-ratedischarge characteristic deteriorates with an increase in the thicknessof the active material layer. On the other hand, in the case of thebatteries of the present invention, the active material layer is dividedinto two and supported by a pair of the outer electrode plates.Accordingly, there is no need to increase the thickness of the activematerial layer in order to increase the battery capacity.

EXAMPLE 14

[0234] (i) Production of Outer Electrode Plate

[0235] LiCoO₂ as a positive electrode active material, carbon powder asa conductive agent, P(VDF-HFP) and N-methyl-2-pyrrolidone were mixed togive a positive electrode mixture. The weight ratio of the activematerial: the conductive agent: P(VDF-HFP) was set to be 100:5:8.

[0236] A band-shaped, film-type, aluminum current collector having awidth of 200 mm and a thickness of 30 μm, was used as a metal sheet. Atthe center of the band-shaped metal sheet, a crease line parallel withthe longitudinal direction was formed. On one surface of this metalsheet, a resin layer comprising polypropylene with a thickness of 50 μmwas laminated, except for its position to be connected to an externalterminal.

[0237] Subsequently, as shown in FIG. 19, the positive electrode mixturewas intermittently applied on the positions, symmetrical with respect tothe crease line, of the other surface of the metal sheet to successivelyform positive electrode active material layers aligned in two rows,thereby producing an outer electrode plate assembly. Each of thepositive electrode active material layers thus formed was in the shapeof a square of 86 mm×86 mm, having a thickness of 120 μm.

[0238] The spacing provided in the row direction between the positiveelectrode active material layers was 18 mm, and the spacing provided inthe width direction was 7 mm, including the crease line.

[0239] (ii) Production of Negative Electrode

[0240] A negative electrode similar to that of Example 1 was produced.

[0241] (iii) Production of Electrode Plate Group

[0242] As shown in FIG. 19, a paste comprising P(VDF-HFP) mixed withN-methyl-2-pyrrolidone was successively applied so as to completelycover each of the positive electrode active material layers, which wasthen dried to form a separator layer in the shape of a square of 89×89mm, having a thickness of about 25 μm.

[0243] Then, a polypropylene film having a width of 5 mm and a thicknessof 50 μm was successively disposed as an adhesive so as to surround thetwo positive electrode active material layers of each of the outerelectrode plate units.

[0244] Next, the above negative electrode was successively placed oneach of the separator layers in one of the rows of the outer electrodeplate assembly.

[0245] Then, positions to be cut of the outer electrode plate assemblywas partly cut off, successively, starting from its junction with thecrease line at the center through one end of the current collector, andeach of the outer electrode plate units was folded at the crease line.As a result, one of the positive electrode active material layers wasplaced on the negative electrode with the separator layer interposedtherebetween, and the polypropylene films disposed on the peripheralportions of the outer electrode plates faced each other. Thereafter, theelectrode plate group thus stacked was successively heated under apressure of 60 gf/cm² until its surface temperature reached 120° C., andintegrated so as to be flattened.

[0246] (iv) Joining of Peripheral Portions

[0247] Each of the outer electrode plates was pressed for 3 seconds at220±5° C. under 10 kgf/cm² at its peripheral portion, except for theside corresponding to the crease line, and the peripheral portions werejoined by melting the polypropylene film. Herein, an unjoined region wasreserved for injecting a non-aqueous electrolyte. From the unjoinedregion, the non-aqueous electrolyte was injected under reduced pressure,and heated to 60° C. or higher to cause the gelation of P(VDF-HFP) inthe electrode plate and separator layer. As the non-aqueous electrolyte,the same one as that used in Example 1 was employed. Thereafter, thepressure inside the battery was reduced, and the unjoined region wassealed. As a result, an assembly of Batteries P as shown in FIG. 14having a completely sealed structure was produced. The assembly ofBatteries P was separated at the end of the process.

[0248] Thus, Battery P in the shape of a square of 100 mm×96 mm, havinga thickness of 0.6 mm, was produced.

EXAMPLE 15

[0249] Battery Q in the shape of a square of 95 mm×93 mm, having athickness of 0.6 mm was produced in the same manner as in Example 14,except that, in the outer electrode plate assembly, the spacing providedin the row direction between the positive electrode active materiallayers was 12 mm, the spacing provided in the width direction was 7 mmincluding the crease line, and the peripheral portions of the outerelectrode plates were joined by ultrasonic welding, instead of using thepolypropylene film.

EXAMPLE 16

[0250] Battery R in the shape of a square of 94 mm×92 mm, having athickness of 0.6 mm was produced in the same manner as in Example 14,except that, in the outer electrode plate assembly, the spacing providedin the row direction between the positive electrode active materiallayers was 10 mm, the spacing provided in the width direction was 7 mmincluding the crease line, and the peripheral portions of the outerelectrode plates were joined by laser welding, instead of using thepolypropylene film.

Comparative Example 2

[0251] The electrode plate group assembly produced in Example 1 wasseparated into individual electrode plate groups. Then, the electrodeplate group was covered by an outer jacket with a thickness of 150 μm,comprising an aluminum foil and polypropylene layers on both surfacesthereof. Subsequently, a non-aqueous electrolyte was injected into theouter jacket and heated to 60° C. or higher to cause the gelation ofP(VDF-HFP) in the electrode plate and separator layer, followed bysealing the outer jacket. Since the outer electrode plate was alsoenclosed in the outer jacket by this step, a positive electrode lead wasalso connected to the outer electrode plate, and the positive electrodelead and the negative electrode lead were drawn from the outer jacket tothe outside. This gave Battery S in the shape of a square of 100 mm×96mm, having a thickness of 0.9 mm.

[0252] The weight reduction rate, capacity retention rate after storageand capacity retention rate after cycles of Batteries P to S weremeasured in the same manner as in the case of Batteries A to L.

[0253] The measured results of the weight reduction rate, capacityretention rate after storage and capacity retention rate after cycles ofBatteries P to S are shown in TABLE 5, together with the energy densityand thickness thereof. TABLE 5 Capacity Capacity Weight retentionretention Energy Battery reduction rate after rate after densitythickness Battery rate (%) storage (%) cycles (%) (Wh/l) (mm) P 0.2 8585 360 0.6 Q 0.2 90 87 390 0.6 R 0.2 90 87 400 0.6 S 0.2 85 85 278 0.9

[0254] As shown in TABLE 5, each of the batteries of the presentinvention is thin and has a high energy density, and furthermore, itexhibits capacity retention rates comparable to or higher than those ofthe battery of the comparative Example. Additionally, it is shown thateach of the batteries in which the peripheral portions were joined bywelding, has a low weight reduction rate and therefore has highair-tightness. This means that the batteries of the present example havebeen significantly improved in reliability.

[0255] Furthermore, it is shown that employing the bending structure, asis done in the present invention, enables reduction of the peripheralportion of the outer electrode plate required for the joining, therebymaking it possible to reduce the battery area.

INDUSTRIAL APPLICABILITY

[0256] As described above, the present invention provides a high-energydensity, thin non-aqueous electrolyte battery which has been reduced inthickness and area as compared with the conventional ones and has asimplified outer jacket structure. The battery in accordance with thepresent invention is particularly improved in the reliability of thesealed joined portion and in the minor short circuit problem thereof.Furthermore, according to the present invention, a high energy density,thin non-aqueous electrolyte battery having a simplified outer jacketstructure can be produced by a continuous process which requires a lessnumber of man-hours.

1. A non-aqueous electrolyte battery comprising: an outer jacketcomprising a metal sheet and having two primary flat portions facingeach other; two active material layers of a first polarity respectivelycarried on inner surfaces of said flat portions; an electrode plate of asecond polarity disposed in a position facing with each of said activematerial layers; and a separator layer interposed between each of saidactive material layers and said electrode plate of a second polarity,said outer jacket serving as a current collector of said active materiallayers.
 2. The non-aqueous electrolyte battery in accordance with claim1, further comprising: an additional electrode plate of a first polaritydisposed adjacent to said electrode plate of a second polarity with aseparator layer interposed therebetween; and an additional electrodeplate of a second polarity disposed adjacent to said additionalelectrode plate of a first polarity with a separator layer interposedtherebetween in a double-stacked form.
 3. The non-aqueous electrolytebattery in accordance with claim 1, further comprising a leadelectrically connected to said electrode plate of a second polarity, oneend of said lead protruding outside from said outer jacket, and saidlead being insulated from said outer jacket with resin.
 4. Thenon-aqueous electrolyte battery in accordance with claim 3, wherein saidlead is provided with an overcurrent breaking device sealed with resinat a portion thereof sandwiched between peripheral portions of saidouter jacket.
 5. The non-aqueous electrolyte battery in accordance withclaim 1, wherein at least one of said separator layer and said activematerial layers contain a polymer electrolyte.
 6. The non-aqueouselectrolyte battery in accordance with claim 5, wherein said polymerelectrolyte is a gel electrolyte comprising a liquid non-aqueouselectrolyte and a polymer retaining the same.
 7. The non-aqueouselectrolyte battery in accordance with claim 1, wherein said outerjacket comprises a pair of metal sheets having flat portions facing eachother or a single metal sheet folded so as to have two flat portionsfacing each other, and peripheral portions facing each other of saidpair of metal sheets or peripheral portions facing each other of saidsingle metal sheet are joined.
 8. The non-aqueous electrolyte battery inaccordance with claim 7, wherein said peripheral portions facing eachother are joined by laser welding or ultrasonic welding.
 9. Thenon-aqueous electrolyte battery in accordance with claim 1, wherein saidmetal sheet has a thickness of 10 to 100 μm.
 10. A method of producing anon-aqueous electrolyte battery comprising the steps of: (1a) forming anactive material layer of a first polarity on a flat portion of onesurface of a metal sheet except for a peripheral portion thereof,thereby producing an outer electrode plate; (2a) producing an electrodeplate of a second polarity; (3a) preparing a pair of outer electrodeplates, disposing one of the outer electrode plates and the other outerelectrode plate so as to face each other, with said active materiallayers disposed facing inwardly, and sandwiching said electrode plate ofa second polarity by said pair of outer electrode plates facing eachother, with a separator layer interposed therebetween; and (4a) joiningperipheral portions of said pair of outer electrode plates facing eachother.
 11. The method of producing a non-aqueous electrolyte battery inaccordance with claim 10, wherein, in the step (1a), a plurality ofactive material layers of a first polarity are intermittently formed ona flat portion of one surface of a band-shaped metal sheet except for aperipheral portion thereof, thereby producing an outer electrode plateassembly comprising a plurality of outer electrode plate units alignedin a row and, in the step (3a), a pair of said outer electrode plateassemblies are prepared, each outer electrode plate unit of one of saidouter electrode plate assemblies and each outer electrode plate unit ofthe other outer electrode plate assembly are successively disposed so asto face each other, with active material layers thereof disposed facinginwardly, and said electrode plate of a second polarity is successivelysandwiched by a pair of outer electrode plate units facing each other,with a separator layer interposed therebetween.
 12. The method ofproducing a non-aqueous electrolyte battery in accordance with claim 10,wherein, in the step (3a), an additional electrode plate of a firstpolarity is disposed adjacent to said electrode plate of a secondpolarity, with a separator layer interposed therebetween, and anadditional electrode plate of a second polarity is disposed adjacent tosaid additional electrode plate of a first polarity, with a separatorlayer interposed therebetween.
 13. The method of producing a non-aqueouselectrolyte battery in accordance with claim 10, wherein, in the step(3a), a paste comprising a starting material of said separator layer isapplied on said active material layer of a first polarity or saidelectrode plate of a second polarity to form said separator layer. 14.The method of producing a non-aqueous electrolyte battery in accordancewith claim 13, wherein said starting material of said separator layercontains a gel-forming agent.
 15. A method of producing a non-aqueouselectrolyte battery comprising the steps of: (1b) preparing a metalsheet provided with a crease line or an imaginary crease line at whichsaid sheet is to be folded so as to have two flat portions facing eachother; (2b) forming a pair of active material layers of a first polarityon said flat portions, symmetrical with respect to said crease line orimaginary crease line, of one surface of said metal sheet except forperipheral portions thereof, thereby producing an outer electrode plate;(3b) producing an electrode plate of a second polarity; (4b) foldingsaid outer electrode plate at said crease line or imaginary crease lineto sandwich said electrode plate of a second polarity by said pair ofactive material layers with a separator layer interposed therebetween;and (5b) joining peripheral portions of said outer electrode platefacing each other.
 16. The non-aqueous electrolyte battery in accordancewith claim 15, wherein, in the step (1b), a band-shaped metal sheet isprepared, which is provided with a crease line or an imaginary creaseline parallel with a longitudinal direction, in the step (2b), pluralpairs of active material layers of a first polarity are intermittentlyformed on flat portions, symmetrical to said crease line or imaginarycrease line, of one surface of said band-shaped metal sheet except forperipheral portions thereof, thereby producing an outer electrode plateassembly comprising a plurality of outer electrode plate units alignedin a row and, in the step (4b), said electrode plate of a secondpolarity is successively sandwiched by a pair of active material layersof each outer electrode plate unit, with said separator layer interposedtherebetween.
 17. The method of producing a non-aqueous electrolytebattery in accordance with claim 15, wherein, in the step (4b), anadditional electrode plate of a first polarity is disposed adjacent tosaid electrode plate of a second polarity with a separator layerinterposed therebetween, and an additional electrode plate of a secondpolarity is disposed adjacent to said additional electrode plate of afirst polarity with a separator layer interposed therebetween.
 18. Themethod of producing a non-aqueous electrolyte battery in accordance withclaim 15, wherein, in the step (4b), a paste comprising a startingmaterial of said separator layer is applied on said active materiallayer of a first polarity or said electrode plate of a second polarity,thereby forming said separator layer.
 19. The method of producing anon-aqueous electrolyte battery in accordance with claim 18, whereinsaid starting material of said separator layer contains a gel-formingagent.